Zinc condenser



Patented Dec. 15,1925.

UNITED STATES 1,565,928 PATENT oFFica.

HARRY A. GRINE, OF CLARKSBURG, WEST VIRGINIA, ASSIGNOR TO THE 'GRASSELLICHEMICAL COMPANY, OF CLEYELAND, OHIO, A CORPORATION OF OHIO.

ZINC CONDENSER.

No Drawing.

'To all whom it may concern:

larly directed to an improved condenser for use in the retort or mufllesmelting of oxidized zinc ores to produce metallic zinc, the ,principalobject of the invention being the provision of a condenser of this typeand purpose which shall have a high content of zinc-bearing material andlow clay content. A further object of the invention is the provision ofsuch a condenser which ,shall have a greater heat conductivity, greatercondensing efficiency, and shall be capable of re-use when broken up,with a minimum of low Zinc-bearing materials in the broken condenserproduct which is to be re-ch'arged. Other objects of the invention willappear hereinafter. To the accomplishment of the foregoing and relatedends, said invention,

then, consists of the means hereinafter fully described and particularlypointed out in the claims, thefollowing description setting forth indetail one method and one product exemplifying my invention, suchdisclosed procedure and productconstituting, however, but o'neof variousapplications to the principles of my invention. a The present practiceof retort or muffle smelting of oxidized zinc oresfto produce metalliczinc involves the introduction of the zinc ores and reducing fuel intoaretort or mufile which is: mounted in a furnace chamber in which thetemperature is maintained at'the proper heat for reduction of the ore.Condensers are set in the mouth or open end of the mufiles of retortsand luted thereto with finely-ground anthracite culm which forms a jointbetween retort and condenser which is impervious to "zinc vapors underthe low pressure within the -retorts. These condensers project withoutthe fur nace chamber and cause sufiicient dro in temperature of the zincvapors issuing rom composition which is high Application filed April 3,1924. Serial No. 703,979.

the retorts to condense them and also serve to retain the metal aftercondensation until drawn. The present condensers consist in compositionofabout nine parts by volume of burned clay or grog to seven parts ofraw plastic refractory clay. Neither of these materials contain zinc insmeltable quantity, only a very small per cent being contained inreclaimed retort or condenser material used as grog in the making of newcondensers. The burned clay may be either new material used for thefirst time, or it may be all or partly burned clay material recoveredfrom broken retorts or condensers which have been used.

At the end of each days operations the crmdensers are removed from themouth of the retorts'ormuiiles to allow the removal of the residues fromthe muliics, after which the retorts are charged with new ore and fuel.111 removal a number of the condensers are broken, and certaincondensers are discarded because of the accumulation of 'zinc oxide,zinc dust or blue powder and metallic'zinc on the inside ofthecondenser, which material has a higher melting point than the metallicZinc and gradually covers the condenser with a coating up to one inch inthickness. The broken and discarded condensers are broken up and thecondenser man selects the portionswith the heaviest deposits of zincthereon, these selected portions being broken into small pieces and thenrecharged into the furnace along with the new ore and fuel. In this waya certain amount of the deposits on the condensers are saved for therecovery of zinc contained.

My improved condenser is formed ,of a in zinc bearing materials andrelatively low in refractory clay and other low or non-zinc-bearingmaterials, which allows the condensers after use to be completely brokenupa'nd recharged, with a saving of practically all of the residues onthe condenser and of the zinc content in the condenser itself. Myimproved condenser may be formed of a mixture containing approximately80 per cent to 85 per cent of zinc-bearing material, assaying 25 percent or more zinc, such for example as broken used ore condensers,calcined Joplin ore, which contains about 68 per cent zinc and a smallamount of finely pulverized plastic clay as a' bonding material. I usethese materials in the proportions of about 45% of the broken used orecondenser, 45%

of new ore and 10% of plastic bonding clay.

A condenser mixture formed of these materials will have approximately52% or 53% zinc content before use and a zinc content after use forseven or eight days of about Various bonding materials may be used,such, for example, as fire clays or bentonite, and these and others havebeen found entirely suitable for this purpose.

After condensers of my composition are discarded they are broken up topass a fourmesh screen, and this crushed material is then mixed with oreand charged into the furnace, thus returning to the furnace all of thezinc material.

In making m condensers I may use some of the discarde condenser materialcrushed to pass a four-mesh screen, which is then thoroughly mixedwithcalcined zinc ore or zinc ash, or materials of a similar nature,which has been crushed to pass a QO-mesh screen, or may use straightzinc ore, and then mixed with plastic clay or other bonding materials,which have been crushed to pass a 40 to (SO-mesh screen. These variousmaterials are then pugged through a wet mixing pug mill in the usualmanner and allowed to stand for several days and then re-pugged, afterwhich the material may be molded into condensers in the machine commonlyused for this purpose. After molding the condensers are placed in adrying room and baked at a temperature of from 100 to 140 F. for 10 to15 days, and then given a second baking at a higher temperature of from150 to 175 F. before use.

My condensers have a higher strength than those now in use, and in thisway effect a considerable saving, as less are broken in handling. Theyalso have a greater heat conductivity since the walls may be thinnerbecause of the greater strength of the material. In addition, thesecondensers have a higher condensing efficiency because of the greaterheat conductivity of the material and the thinner walls of thecondenser. The use of thinner walls effects a saving in the breaking upof the condensers after use for subsequent recharging and also inconcentrating costs where wet concentration or hand chipping andselection of condensers is practiced.

In addition to the above advantages I effect a considerable saving inzinc, which is in present practice lost because of pieces of condenserdiscarded and not recharged, and a greater efficiency in thefurnacingoperation because of the absence of considerable amounts of refractorymaterials which are unavoidably included with the Zinc from thebroken-up condensers under the present practice and availability of theretort capacity, which would be occupied by such barren material, forthe smelting of zincbearing material.

Other forms may be employed embodying the features of my inventioninstead of the one here explained, change being made in the form orconstruction, provided the elements stated by any of the followingclaims or the equivalent of such stated elements be employed, whetherproduced by my preferred method or by others embodying steps equivalentto those stated in the following claims.

I therefore particularly point out and distinctly claim as myinvention 1. A composition for zinc condensers comprising broken zinccondenser, zinc ore and a refractory bonding material.

2. A composition for zinc condensers comprising approximately 80 percent zinc bearing material consisting of equal parts of broken zinccondenser and zinc ore and 20 per cent refractory bonding material.

3. A composition for zinc condensers comprising equal parts of brokenzinc condenser and zinc ore, each having a zinc content in excess of 60%and a small amount of plastic refractory clay.

4. A composition for zinc condensers comprising equal parts of brokenzinc condenser and zinc ore, each having a zinc content in excess of60%, and about 10% of plastic refractory clay. 7

Signed by me, this 24 day of March, 1924.

HARRY A. GRINE.

